Free Fatty Acids and Complex Lipids in Patients With Severe Obesity Treated With Roux-En-Y Gastric Bypass: Impact of...

This study investigates the relationship between eight free fatty acids (FFA), triglycerides (TAG), and phosphatidylcholines (PC) after Roux-en-Y gastric bypass (RYGB) to obtain insight into changes in lipid metabolism that might be causally related to postsurgery Type 2 diabetes remission. We measured the FFA, TAG, and PC before and up to 2 years after RYGB in three patient groups: one nondiabetes group (n = 149), one diabetes group with postoperative remission (n = 33), and one diabetes group with persistent diabetes after surgery (n = 20). Pre- and postoperative Pearson's correlations and linear regression models were used to assess the relationship between concentrations of individual FFA, TAG, and PC. At all timepoints, FFA explained more of the variance in PC than in TAG. The level of omega-3 fatty acids was more strongly correlated to TAG in the group with diabetes remission compared to the nondiabetes group. The low plasma concentration of the omega-6 fatty acid dihomo-γ-linolenic acid (DGLA) showed a surprisingly high correlation to both TAG and PC in all three groups. Unexpectedly, in the diabetes group without remission, a nonsignificant relation between saturated stearic acid and monounsaturated oleic acid indicates a possible impaired conversion of stearic acid to oleic acid via the enzyme delta-9-desaturase compared with the two other groups. We conclude that FFA might be involved in regulating the synthesis and metabolism of both TAG and especially PC. Diabetes status might influence the relationship between concentrations of FFA, TAG, and PC, and the data are suggestive of a role for the enzyme delta-9-desaturase in post-RYGB diabetes remission.